1. Field of the Invention
The present invention relates to a liquid discharge head having a plurality of nozzles for jetting a liquid, including, for example, an ink-jet head to be carried, for example, on an ink-jet printer. The present invention relates to a printer such as an ink-jet printer.
2. Description of the Related Art
The ink-jet head is provided with a channel unit which has ink channels communicated with nozzles, and an actuator which is stacked on the channel unit. The ink channel has a common ink chamber to which an ink is supplied from an ink supply source, a plurality of pressure chambers which are provided corresponding to the plurality of nozzles, and a plurality of connecting channels which are provided individually for the respective pressure chambers in order to supply the ink contained in the common ink chamber to the respective pressure chambers. The actuator allows the pressure wave to act on the ink contained in the pressure chamber. Accordingly, the ink contained in the pressure chamber is discharged from the nozzle.
In a certain ink-jet head, the resolution is improved by the following configuration, wherein the ink-jet head has two arrays of pressure chambers and two arrays of nozzles which are aligned in the direction perpendicular to the extending direction of a single common ink chamber, and the respective pressure chamber arrays and the nozzle arrays extend in the extending direction of the common ink chamber. In order to improve the resolution for the nozzle group which forms the two nozzle arrays, the nozzles, which form the respective nozzle arrays, are disposed in a zigzag or staggered arrangement, and the pressure chambers, which form the respective pressure chambers, are also disposed in a zigzag or staggered arrangement in the same manner as described above. The connecting channels, which are provided corresponding to the pressure chambers which form one array, are arranged to extend in the direction perpendicular to the extending direction of the common ink chamber between the mutual pressure chambers which form the other array.
In order to improve the resolution, it is also effective to decrease the ink droplets by decreasing the nozzle diameter. However, if the nozzle diameter is decreased, the channel resistance of the nozzle is increased in accordance therewith. On the other hand, in order that the pressure wave, which is allowed to act on the ink contained in the pressure chamber, is transmitted to the nozzle to discharge a desired amount of the ink, it is desirable that the channel resistance, which is approximately the same as that of the nozzle, is also established for the connecting channel which is disposed on the upstream side of the pressure chamber. For this reason, a throttle channel, which has a small cross-sectional area of the channel, is generally formed at a part of the connecting channel of the channel unit.
In another inkjet head, a connecting channel is arranged to be inclined with respect to the extending direction of a common ink chamber as viewed in a plan view in order to lengthen a throttle channel of the connecting channel and increase the channel resistance of the connecting channel. Accordingly, even when the nozzle diameter is decreased, then the ink is discharged from the nozzle appropriately when the pressure wave is allowed to act on the ink contained in a pressure chamber, and the ink contained in the ink channel stably flows.
However, in the case of the former ink-jet head, it is possible to realize the highly densified arrangement of the nozzles, while it is difficult to secure a large length of the connecting channel. Therefore, it is difficult for the connecting channel to establish any channel resistance which is approximately the same as that of the nozzle.
In the case of the latter ink-jet head, the connecting channel is arranged while being inclined. In other words, the pressure chamber array is arranged while being deviated or deflected in the extending direction of the common ink chamber with respect to the common ink chamber. In the case of the arrangement of the common ink chamber, the pressure chamber array, and the connecting channels of the another ink-jet head, it is feared that the channel unit may be large-sized in the direction of arrangement of the pressure chamber array, i.e., in the extending direction of the common ink chamber, and the whole ink-jet head may be large-sized.